1. Field of Invention
This invention relates to survivor locator lights, specifically to the water-activated automatic electrical switching methods. Nevertheless, a manual override device is also included in this invention.
2. Description of Prior Art
Life vests and life rafts carried in aircraft and ships as part of the emergency equipment are normally equipped with survivor locator lights. These lights will facilitate rescuers to locate survivors at night.
There are such lights on the market. They use battery as power source and employ one of the following switching methods for turning the light on:
(a) By manual action--This type of switching methods must be actuated manually. An unconscious survivor will not be able to operate it, not to mention where to find the switch at night.
(b) By electronic moisture sensing circuits--They must consume electric energy to function. In emergency situations an extra bit of energy may just save a life. U.S. Pats. Nos. 3,671,912 to LaSota (1971), 3,914,592 to Maxey (1974), 4,001,531 to Crockett (1975), 4,234,819 to Maxey (1979), 4,585,190 to Hansen (1984), and 4,714,914 to Boe (1986) are all operated in this manner.
(c) By water conductivity--Water is not a good conductor, especially in low voltage application such as this light. Reduced illumination will result due to water resistance. U.S. Pats. Nos. 3,437,769 to Vincent (1967), 3,492,449 to Kenny (1968), 3,622,721 to Hodes (1965), 4,427,976 to Lord (1979), and 4,638,291 to Puscasu (1984) are of this design but for different applications.
(d) By water-activated battery--When this type of battery, magnesium-cuprous chloride battery for example, is immersed in water, chemical reaction will take place to generate electricity and, as a result, produce substantial amount of magnesium and copper compounds into the water in the immediate vicinity of the survivor's mouth, nose and eyes because most of such batteries are attached to life jackets at a location only few inches from the front of the wearer's head.